1. Field of the Invention
The invention relates to a casting tool for the production of workpieces cast from light-metal alloys and, in particular for the motor vehicle industry, wherein at least one positioning element is provided to fix at least one preformed core part remaining in the cast workpiece in a predetermined position within the casting tool, as well as a method for producing workpieces cast from light-metal alloys having at least one preformed core part remaining in the cast workpiece is held in a predetermined position within a casting tool.
2. Discussion of Background Information
For the production of workpieces from light-metal alloys, it is already known to hold preformed core parts in a casting tool with the aid of positioning elements, such that a light-metal alloy melt can be cast around the core parts.
From EP 0 922 591 A, a rim made of a light-metal alloy is known, for instance, wherein a core part comprises fixedly arranged positioning elements in order to be positioned within the mold. Such positioning elements arranged in the core part, however, have relatively large peripheries, thus forming weak material points such that very high stress peaks will occur in those regions of the rim under load, in particular under dynamic bending and torsional stresses.
A similar casting method has already become known from WO 01/66283 A1 and AT 409 728 B, respectively, wherein fixedly arranged positioning elements are likewise provided in the core part. These positioning elements comprise air discharge channels for the escape of expanded air. This method, however, involves high expenditures in terms of manufacturing technology, with equally high stress peaks occurring because of the positioning elements being fixedly arranged in the cores part.
From US 2004/0099398 A1, a positioning element for a sand core is known, wherein the positioning element is fixed within the sand core during the production of the latter, and via which a connection with the casting tool can be created.
DE 42 01 278 A1 describes supports or positioning elements for stabilizing casting cores in the production of molded articles. There, the pin-shaped positioning elements, which are fastened in the casting tool in the manner of a nail, each comprise a cast-in element extending transversely to the longitudinal direction of the shaft of the positioning element, which is firmly melted in the molded article to provide a firm connection of the positioning element in the molded article to be cast.
Furthermore, it is also known to form hollow spaces during the production of cast workpieces by the aid of core parts which will again be removed from the cast workpiece, such as, sand cores. Yet, comparatively large openings are required to remove the same, for which reason high stress peaks will again occur in the region of such openings.